Advances in mass spectrometry instrumentation and methods have pushed mass spectrometry to the forefront in modern biomedical research. Electrospray and matrix-assisted laser desorption have dramatically extended the range of molecular weights that can be analyzed by mass spectrometry. Electrospray instruments extend the range to well over 50,000 Daltons. Macromolecules introduced into the mass spectrometer using an electrospray source carry multiple charges such that the compounds are within the mass-to-charge ratio range of a quadrupole mass filter. Tandem mass spectrometry uses two analytical compartments, one to select ions and a second to measure the mass-to-charge ratio of fragments produced by collision of the preselected ion with an inert gas. Tandem mass spectrometers are typically triple quadrupole instruments. The ion of interest is generated in the ion source and selected in the first mass filter, fragmented in the second sector, and analyzed with the second resolving quadrupole. Combining liquid chromatography and mass spectrometry provides a very powerful tool to investigators addressing biomedical questions, and improves or extends the capabilities of both methodologies. Compounds separated by liquid chromatography can be identified by molecular mass, and since the compounds enter the mass spectrometer over time, the efficiency of ionization is improved. Coupled with the appropriate buffers, liquid chromatography desalts the sample, again increasing sensitivity. At this time liquid chromatography/mass spectrometry instrumentation is not available on the University of Mississippi Medical Center Campus. NIH funded investigators have expressed a need for convenient and more efficient access to a mass spectrometry facility for specific analysis including the following: Identification of phosphorylation sites on Janus Kinase molecules;Determine the residues responsible for the hyperphosphorylation of coilin, which is involved in Cajal body formation;Identification and quantification of arachidonic acid metabolites and estrogenic compounds which are proposed to contribute to hypertension;and identification of novel circulating plasma compound(s) produced by directly infusing leptin into the brains of diabetic rats that stimulate glucose uptake in isolated cells independent of insulin. The requested Applied Biosystems 4000 Q Trap LC/MS/MS will provide the instrumentation needed to carry out the analysis requested by our NIH funded investigators. PUBLIC HEALTH RELEVANCE: The University of Mississippi Medical Center, the major biomedical research facility for the state of Mississippi, is committed to basic and clinical research that addresses the prevalent health issues of the public at large, as well as those of Mississippi's disproportionately high medically under-served population. Modern analytical instrumentation is essential for effective biomedical research, and specifically the combination of liquid chromatography and mass spectrometry, a most powerful tool for biomedical investigation, is not available to UMMC investigators. The existing liquid chromatography instrumentation available to UMMC investigators is greater than ten (10) years old, service is not available and the instrument (API 365) lacks the necessary sensitivity and flexibility of operating modes for some of the applications requested by NIH funded investigators.